Download Prism Sound Titan Specifications

Titan
Operation Manual
by Ian Dennis
This manual is also available as 'on-line help' from the Titan
Control Panel app. You can access the on-line help from the
'Help' button in the top right-hand corner of the app.
Table of Contents
Part 1
General information
2
Part 2
Introduction to Titan
6
1
Features
................................................................................................................................. 6
2
System
.................................................................................................................................
requirements
7
3
About
.................................................................................................................................
this manual
7
Part 3
Quick start guides
1
Quick
.................................................................................................................................
start for Mac
10
2
Quick
.................................................................................................................................
start for Windows
10
Part 4
Installation procedures
1
Mac.................................................................................................................................
installation
12
2
Windows
.................................................................................................................................
installation
14
3
Operating
.................................................................................................................................
multiple units
19
4
Software
.................................................................................................................................
and firmware updates
19
Part 5
Titan hardware
1
Signal
.................................................................................................................................
path architecture
22
Analogue
.......................................................................................................................................................
inputs
Overkiller
................................................................................................................................................
High-pass
................................................................................................................................................
filter
MS
................................................................................................................................................
matrix
Digital
.......................................................................................................................................................
inputs
Sample-rate
................................................................................................................................................
converter
DI................................................................................................................................................
synchronization
Analogue
.......................................................................................................................................................
outputs
Digital
.......................................................................................................................................................
outputs
Sample-rate
................................................................................................................................................
converter
Word-length
................................................................................................................................................
DO
................................................................................................................................................
synchronization
Output
.......................................................................................................................................................
mixers and routing matrix
Assignable
.......................................................................................................................................................
level control
Headphone
.......................................................................................................................................................
outputs
Metering
.......................................................................................................................................................
system
MDIO
.......................................................................................................................................................
expansion slot
10
12
22
22
23
23
23
23
24
24
24
25
25
26
26
26
27
27
27
28
2
Synchronization
................................................................................................................................. 29
3
Front
.................................................................................................................................
panel
29
4
Rear
.................................................................................................................................
panel
31
5
Stand-alone
.................................................................................................................................
operation
32
6
Rack
.................................................................................................................................
mounting
32
Part 6
Titan software
Fuses
.......................................................................................................................................................
and ratings
32
34
1
Titan
.................................................................................................................................
Control Panel app
34
Unit
.......................................................................................................................................................
settings
Inputs
.......................................................................................................................................................
tab
Outputs
.......................................................................................................................................................
tab
Mixer
.......................................................................................................................................................
tabs
35
37
38
39
2
Titan
.................................................................................................................................
drivers
39
Part 7
Technical topics
1
Stability
.................................................................................................................................
and latency
42
2
Clocking
.................................................................................................................................
and jitter
43
3
Dither
.................................................................................................................................
and noise-shaping
45
4
Analogue
.................................................................................................................................
interconnections
48
5
Digital
.................................................................................................................................
interconnections
50
Part 8
Specifications
54
Index
60
42
Part
1
General information
Prism Sound Titan
1
Operation Manual
Revision 1.00
General information
Manual revision history
Rev Date
1.00 8th December 2013
Author
I.G.Dennis
Notes
Product Launch
Support contacts
Prism Media Products Limited
The Old School
Stretham
Cambridge CB6 3LD
UK
Prism Media Products Inc
21 Pine Street
Rockaway
NJ 07866
USA
Telephone: +44 1353 648888
Fax: +44 1353 648867
Telephone: +1 973 983 9577
Fax: +1 973 983 9588
Email: [email protected]
Web: http://www.prismsound.com
Or contact your local Prism Sound distributor as detailed on the website.
WARNING!
TO PREVENT FIRE OR SHOCK HAZARD DO NOT EXPOSE THIS EQUIPMENT TO
RAIN OR MOISTURE. DO NOT REMOVE THE COVER. NO USER-SERVICEABLE
PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
© 2013 Prism Media Products Ltd
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Operation Manual
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Statements of conformity
This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against interference in a residential area. This device generates and uses radio frequency energy
and, if not installed and used in accordance with the instructions, may cause interference to radio or
TV reception. If this unit does cause interference to radio or TV reception, please try to correct the
interference by one or more of the following measures:
a) Reorient or relocate the receiving antenna.
b) Increase the separation between the equipment and the receiving antenna.
c) Plug the equipment into an outlet on a different circuit from the receiver.
d) If necessary, consult your dealer or an experienced radio or TV technician.
CAUTION: Changes or modifications to this equipment not expressly approved by the manufacturer
could void the user's authority to operate this equipment.
THIS DIGITAL APPARATUS MEETS ALL CLASS B LIMITS FOR RADIO NOISE EMISSIONS AS
LAID DOWN IN THE RADIO INTERFERENCE REGULATIONS OF THE CANADIAN DEPARTMENT
OF COMMUNICATIONS.
CET APPAREIL NUMÉRIQUE RESPECTE TOUTES LES EXIGIENCES APPLICABLES AUX
APPAREILS NUMÉRIQUES DE CLASSE B SUR LE BROUILLAGE RADIOELECTRIQUE EDICTE
PAR LE MINISTERE DES COMMUNICATIONS DU CANADA.
Prism Media Products Ltd hereby declares that this equipment conforms to the following standards:
EN55103-1, environment category E4
EN55103-2, environment category E4
NOTE: The use of this equipment with non-shielded interface cabling is not recommended by the
manufacturer and may result in non-compliance with one or more of the above directives. All coaxial
connections should be made using a properly screened 75R cable with the screen connected to the
outer of the connector at both ends. All analogue XLR and jack connections should use screened
cable with the screen connected to pin 1 of the XLR connector, or the jack outer, at both ends.
Trademarks
SNS, Super Noise Shaping, Overkiller and CleverClox are trademarks of Prism Media Products Ltd.
Windows, XP and Vista are trademarks of Microsoft Corporation.
Mac, OS X, and Macbook are trademarks of Apple Computer Inc.
All trademarks acknowledged.
© 2013 Prism Media Products Ltd. All rights reserved.
This manual may not be reproduced in whole or part, in any medium, without the written permission of
Prism Media Products Limited.
In accordance with our policy of continual development, features and specifications are subject to
change without notice.
© 2013 Prism Media Products Ltd
1.3
Part
2
Introduction to Titan
Prism Sound Titan
2
Operation Manual
Revision 1.00
Introduction to Titan
Titan is a USB multi-channel audio interface for Windows PC and Mac. As well as eight analogue line
inputs and outputs, Titan provides four high-quality microphone preamplifiers, two high-impedance
instrument inputs, as well as a host of advanced synchronization and monitoring facilities.
Titan is intended to provide 'studio in a box' functionality for the digital audio workstation (DAW) user.
That's not so unusual - there are many other interfaces on the market which provide similar
functionality. However, Titan is unique among them in providing Prism Sound's unique pedigree of
conversion, analogue, clocking and signal processing to the DAW user in an integrated package, with
the plug-and-play convenience of an ordinary USB sound card.
For a more detailed summary of Titan's features, continue to the Features section.
For directions for getting started quickly, see the Quick start guides.
For detailed hardware and software installation procedures, see the Installation procedures.
For full details of the hardware controls and connections, as well as a block diagram, look at the
Hardware section.
To learn about the control software, see the Titan Control Panel section.
2.1
Features
Titan provides eight line input channels and eight line output channels, which can be operated in
balanced or unbalanced mode, and each of which can be used with professional ('+4dBu') or
consumer ('-10dBV') signal levels. Four of the input channels have selectable microphone
preamplifiers, and two of these also have high-impedance, unbalanced instrument input jacks. 24-bit
conversion is used throughout, and sample rates up to 192kHz are supported.
Stereo digital I/O is provided in both S/PDIF and optical (TOSLINK) formats. The S/PDIF input can
also accept professional AES3 signals, and the S/PDIF output can be switched to AES3 mode if
required. The optical connectors can alternatively carry eight channels of ADAT I/O at 44.1k or 48kHz
sample rates, or four channels at 88.2kHz or 96kHz. A high-quality sample-rate converter can be
assigned to the S/PDIF input or output if required.
Titan has a dedicated stereo analogue headphone output, with two stereo headphone jacks, each
with its own level control.
Titan incorporates the new Prism Sound MDIO (multi-channel digital IO) expansion slot, which allows
additional and future host interface formats to be accommodated.
Under Windows, Titan can be accessed by any software applications with WDM (Windows) or ASIO
capability. Under Apple OS X, Titan appears as a Core Audio device.
To deal with low-latency requirements in live sound and over-dubbing, Titan has its own fully-featured
mixer for each output channel pair (including digital, ADAT and headphones). When selected, each
mixer allows a low-latency mix of any input channels (as well as the output's associated workstation
feeds) to be sent to the required outputs. Additionally, each output can be switched to follow the
output of any other output's mixer.
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A front-panel volume control can be assigned to any desired analogue or digital outputs, primarily for
use as a stereo or surround monitoring control.
Titan's sample rate (44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz) can be sourced from its
high-stability internal clock, or locked to the stereo digital or ADAT inputs or the BNC Wordclock input.
Clock output is via the S/PDIF output and the BNC Wordclock output (which can also be set to
Baseclock or Superclock modes).
2.2
System requirements
Titan will work with any modern host PC or Mac with a suitable operating system and USB 2.0 or 3.0
port. Macs must be Intel platform and must be running OS X 10.5 Leopard or later; PCs must be
running Windows Vista, 7, 8 or later (32-bit or 64-bit).
This is not to say that the computing power of the host is unimportant, but it is more a requirement of
the audio applications than of Titan. If you need to record or playback large numbers of channels,
perhaps at high sample rates or with a lot of processing or plug-ins, you will need a host computer
with a fast processor and bus, plenty of RAM, and probably a fast hard disk too. On the other hand,
playback of moderate channel counts at lower sample rates can be accomplished with even a modest
computer.
A good way to gauge this is to be guided by the system requirements of the audio software which you
are intending to use. For more information about this, see the Stability and latency section.
2.3
About this manual
The Titan Operation Manual is provided in two different formats: as a conventional manual in pdf
format, and also as HTML-based 'on-line help' which can be viewed on your computer. The on-line
help version can be launched directly from the Titan Control Panel app by clicking the help [?] button
in the upper right-hand corner of the panel.
The on-line version of the manual is displayed with a navigation panel to the left of the topic pages.
Links within each topic page can be clicked to navigate to pages of interest. The heading bar of each
topic page contains buttons for navigating to the previous or next topics, and for moving back to the
start of the current chapter. Alternatively, the navigation area on the left contains a "Contents" section
which shows a hierarchical map of the entire document from which desired pages can be selected
directly. The navigation area can also be used to select topics using a full keyword index, or by
searching the document for a particular word or phrase. The selection mode is switched using the
controls at the top of the navigation area.
The pdf version can be viewed and printed using the Adobe Acrobat Reader, which can be
downloaded free at www.adobe.com.
Updates of both the on-line and pdf forms of the manual are available from the Prism Sound website
at www.prismsound.com.
© 2013 Prism Media Products Ltd
1.7
Part
3
Quick start guides
Prism Sound Titan
3
Operation Manual
Revision 1.00
Quick start guides
This section contains brief instructions to get up and running quickly. If you need more detailed
instructions, see the Installation procedures section.
3.1
Quick start for Mac
The Titan software can be installed on Macs with Intel processors. You need a spare USB 2.0 or
USB 3.0 port. You must have OS X 10.5 Leopard, or later.
· Connect your Titan to the mains supply and to a USB port on your Mac with the cables provided.
· Insert the installation disc into a DVD-ROM drive on your Mac, or else locate the folder containing
the downloaded package.
· Double-click on the "Titan control app" package.
· Follow the on-screen instructions.
When software installation is complete, the Titan device's ports should be visible in Audio/MIDI Setup
as Core Audio ports.
3.2
Quick start for Windows
To install the Titan software, your PC must be running Windows Vista, 7, 8 (32-bit or 64-bit), or later.
You need a spare USB 2.0 or USB 3.0 port.
· Connect your Titan to the mains supply and to a USB port on your PC with the cables provided.
· Insert the installation disc into a DVD-ROM drive on your PC, or else locate the folder containing
the downloaded installation files.
· If the PC is set to 'Autoplay', installation will begin automatically, otherwise double-click on the
"setup.exe" icon in the root folder of the disc.
· Follow the on-screen instructions.
When software installation is complete, the Titan device's ports should be visible to Windows as
WDM audio devices, and to any suitable applications as ASIO audio ports.
© 2013 Prism Media Products Ltd
1.10
Part
4
Installation procedures
Prism Sound Titan
4
Operation Manual
Revision 1.00
Installation procedures
This section contains detailed installation instructions for your Titan. If you are keen to get going
quickly, you could use the Quick start guides section.
4.1
Mac installation
The Titan Control Panel app can be installed on Macs with Intel processors. You need a spare USB
2.0 or USB 3.0 port. You must have OS X 10.5 Leopard, or later. No driver is required, since OS X
can interface to Titan directly.
The full installation procedure is as follows:
· Connect your Titan to the mains supply and to a USB port on your Mac with the cables provided.
· Insert the installation disc into a DVD-ROM drive on your Mac, or else locate the folder containing
the downloaded package.
· Double-click on the "Prism Sound USB Audio control app" package.
· A dialogue box will guide you through the installation process; click 'Continue':
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· A copy of the EULA will appear, which you should read:
· Agree to the EULA by clicking 'Continue'.
· Having selected an install destination if required, click 'Install' to perform the installation:
· You may need to enter an administrator's name and password.
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· The installation process will then complete:
· When software installation is complete, close the dialogue box.
The Titan device's ports should now be visible in Audio/MIDI Setup as Core Audio ports.
· Remember to register your Titan at http://www.prismsound.com/register.
4.2
Windows installation
The following procedure installs the Titan ASIO and WDM audio drivers, and the Titan Control Panel
app, on your Windows PC. You must have Windows Vista or later (either 32-bit or 64-bit), and a
spare USB 2.0 or USB 3.0 port.
· Connect your Titan to the mains supply and to a USB port on your PC with the cables provided.
· Insert the installation disc into a DVD-ROM drive on your PC, or else locate the folder containing
the downloaded installation files.
· If the PC is set to 'Autoplay' , installation will begin automatically, otherwise double-click on the
"setup.exe" icon in the root folder of the disc.
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· A welcome screen announces that installation is abut to begin. If you wish to proceed, click 'Next':
· You will be asked to agree to the EULA - if you agree, click 'Yes':
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· Confirm your user name and organisation, and click 'Next':
· Choose 'Complete' to perform a default installation. To change the installation location or which
components will be installed, you can choose 'Custom' (not recommended). Click 'Next':
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· Final check. To proceed with installation, click 'Next':
· Installation will then proceed:
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· You may then be prompted to confirm that you would like to install the device driver. Click 'Install':
· Note that, depending on your installation you may have to confirm TWO driver installations, one for
the USB audio driver itself and one for the WDM driver.
· Installation will then complete, click 'Finish':
The Titan device's ports should now be visible to Windows and any applications as both ASIO and
WDM audio ports.
· Remember to register your Titan at http://www.prismsound.com/register.
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Operation Manual
Revision 1.00
Operating multiple units
Operation of multiple Titan units connected to a single host computer is not currently supported.
It is possible that this feature may become available in future software releases.
4.4
Software and firmware updates
From time to time, new versions of the Titan Control Panel app, the Windows driver, or the Titan
firmware itself will be made available. To view the latest versions available, please visit www.
prismsound.com/Titan_downloads. Software and driver updates can be installed by following the
procedures in the previous sections. Updating of the firmware resident in the Titan hardware requires
the use of a bootloader mode of the Titan Control Panel app; detailed instructions for this process are
included with the download.
© 2013 Prism Media Products Ltd
1.19
Part
5
Titan hardware
Prism Sound Titan
5
Operation Manual
Revision 1.00
Titan hardware
This section describes in detail the capabilities of the Titan hardware.
5.1
Signal path architecture
The figure above is a simplified block diagram of the Titan audio signal paths.
Titan is basically a sound card, with all inputs made available to the host computer via the USB host
bus, and all outputs likewise driven from the USB host bus. However, Titan's signal paths contain a
range of enhanced processing and mixing functions, which are described in the following sections.
5.1.1
Analogue inputs
All eight analogue input channels feature balanced line inputs on TRS jacks, with dual switchable
sensitivity to allow connection to professional or consumer line-level sources. The '+4dBu' setting
accommodates professional signals with a nominal level of +4dBu and allows a maximum level of
+18dBu (0dBFS). The '-10dBV' setting accommodates consumer signals with a nominal level of
-10dBV and allows a maximum level of +6dBu (0dBFS).Unbalanced sources are automatically
accommodated.
Input channels 1-4 also have balanced XLR microphone inputs, with gains variable from 10dB to
65dB in accurate 1dB steps, and with individually switchable phantom power. A -20dB pad is also
selectable for each microphone input individually.
Input channels 1 and 2 also have high-impedance front-panel unbalanced instrument jacks, also with
fine and accurate gain control.
Selection of input modes is automatic: line input mode is automatically selected on channels 1-4
whenever a TRS jack is inserted into the rear-panel combo connector, otherwise mic input mode is
selected. On channels 1 and 2, mic input mode is automatically over-ridden whenever a mono jack is
inserted in the front-panel instrument jack.
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The input mode and phantom power state of the input channels is indicated on the front panel of the
unit, and also in the Inputs tab of the Titan Control Panel app. Line, mic and instrument gains are
also adjusted in the Inputs tab, as is selection of the Overkiller, high-pass filter and MS matrix
functions described in the following sections.
5.1.1.1
Overkiller
The analogue input channels include a switchable Prism Sound 'Overkiller' circuit. The Overkiller is
an instantaneous progressive limiter which protects against converter overload by a margin of up to
10dB, gently absorbing transients and allowing recording levels to be raised without risk. The
Overkillers in Titan operate identically to those in other Prism Sound converters; they can be used
with any input mode (line, mic or instrument), and their operating thresholds are automatically
adjusted for any gain setting.
The Overkillers are switched on and off in the Inputs tab of the Titan Control Panel app. A
per-channel indication of Overkiller activity is provided both on the front panel of the unit (below each
meter, if the meters are in 'Input' mode), and also in the Inputs tab. Note that these indicators are
dynamic, and show when the Overkiller is actually limiting.
5.1.1.2
High-pass filter
The analogue input channels have switchable high-pass 'impact filters', which roll off below 80Hz.
These are most useful in mic input mode, in removing unwanted low-frequency content. The filters
are also available in instrument and line modes, which can be useful if, for example, external
microphone pre-amplifiers without filters are used.
The filters are switched on and off in the Inputs tab of the Titan Control Panel app.
In channels 1 and 2, the filters can also provide an RIAA de-emphasis filter selectable as an
alternative to the high-pass filter, allowing them to be used with vinyl decks. The RIAA filter is aligned
to have a gain of 16dB at 1kHz, so that phono cartridges fall within the sensitivity range of the
instrument inputs, as described in the vinyl decks section.
5.1.1.3
MS matrix
Each pair of analogue input channels has a switchable MS matrix. This is intended for use with
'mid-side' stereo microphones, where sum and difference signals are derived from the two input
channels creating left and right output channels. The MS matrices are available when the analogue
inputs are in both mic or line modes, allowing external microphone preamplifiers without matrixing to
be used.
Note that there is no explicit stereo width control provided in the matrix; however width can be
adjusted by balancing the gains of the mid and side inputs - the gain steps of the Titan microphone
preamplifiers are fine and precise. In line input mode, no fine gain adjustment is available, so if the
Titan MS matrix is used with external preamplifiers, these must have fine and accurate gain control if
width adjustment is required.
The MS matrix is switched on and off in the Inputs tab of the Titan Control Panel app.
5.1.2
Digital inputs
TOSLINK and RCA connectors accept two-channel digital audio signals in the S/PDIF format at any
standard sample rate between 44.1kHz and 192kHz. The RCA input can also automatically accept
digital audio in the AES3 (AES/EBU) format using the XLR-RCA adapter supplied.
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The Inputs tab of the Titan Control Panel app contains the control for selecting the RCA or TOSLINK
connector for S/PDIF input, and also indicators to show that the S/PDIF input is unlocked (i.e. no
S/PDIF carrier is recognized) or asynchronous to the unit's sample clock. The unlock indicator is also
shown beneath the digital meter on the unit's front panel (providing that the unit's meters are in Input
mode).
The TOSLINK connector can also accept 8-channel digital input in ADAT format (at 44.1kHz or 48kHz
sample rates) or 4-channel input in ADAT SMUX format (at 88.2kHz or 96kHz sample rates). the
Inputs tab also contains UNL and ASNC indicators for the ADAT/SMUX input function.
Note that ADAT input and output is only possible when operating Titan in one of its specific
ADAT-capable modes. This is to reduce overhead on the host PC or Mac when ADAT input and
output is not required. For more information see the Unit Settings tab of the Titan Control Panel app.
It is possible to configure a sample-rate converter in the S/PDIF input, as described in the following
section.
5.1.2.1
Sample-rate converter
A two-channel sample-rate converter (SRC) can be activated in the S/PDIF input if desired. This
provides very high-quality conversion of any incoming digital audio signal to Titan's current sample
rate. The SRC is selected in the Unit Settings tab of the Titan Control Panel app. Note that the SRC
can be configured in the S/PDIF input, or in the S/PDIF output, but not in both simultaneously.
Note that presence of an SRC in the S/PDIF input is shown by an indicator beneath the digital meter
on the unit's front panel (providing that the unit's meters are in Input mode).
5.1.2.2
DI synchronization
Note that it is necessary to ensure that the sample clock of any digital audio input is synchronous with
Titan's sample clock (unless the SRC is active in the digital input path). This can be achieved either
by synchronizing Titan to the source (by using DI or ADAT sync source), or by synchronizing the
source to Titan's S/PDIF, ADAT or Wordclock output. Titan also has a Wordclock sync input for
synchronization to Wordclock-equipped sources or house syncs.
The Input Settings tab of the Titan Control Panel app contains indicators to show that the S/PDIF or
ADAT input is ASNChronous (i.e. there is an S/PDIF or ADAT signal present but it is not synchronous
with Titan's sample clock).
For more information about synchronization settings, see the Synchronization section and also the
section describing the Unit Settings tab of the Titan Control Panel app.
5.1.3
Analogue outputs
Titan provides eight analogue output channels on TRS jacks, with dual switchable output level to
allow connection to professional or consumer line-level equipment. The '+4dBu' setting produces
professional signals with a nominal level of +4dBu and allows a maximum level of +18dBu (0dBFS).
The '-10dBV' setting provides consumer signals with a nominal level of -10dBV and allows a
maximum level of +6dBu (0dBFS). Connection to unbalanced equipment is automatically
accommodated by a level-compensation 'bootstrapping' circuit.
In normal operation, the analogue outputs are fed directly with individual signals from the host PC or
Mac; however, it is possible to feed the outputs from local digital mixers within the Titan hardware if
desired - this is described in the Output mixers section below. Outputs may also be switched to follow
the mixers of other outputs.
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It is also possible to assign a level control to any desired outputs, primarily for use as a monitor
volume control - this is described in the Assignable level control section below.
Setting of analogue output levels, as well as activation of output mixers and assignment of the level
control are all managed in the Outputs tab of the Titan Control Panel app.
5.1.4
Digital outputs
TOSLINK and RCA connectors output two-channel digital audio in the S/PDIF format at any standard
sample rate between 44.1kHz and 192kHz. The RCA output can also output digital audio in the AES3
(AES/EBU) format using the RCA-XLR adapter supplied. To do this, select 'AES3' instead of 'S/PDIF'
in the DO1/2 strip of the Outputs tab of the Titan Control Panel app. This causes the carrier voltage
to be increased to the AES3 level, and the Channel Status to adopt the professional AES3 format
instead of the consumer format of S/PDIF.
The TOSLINK connector can alternatively output 8-channel digital audio in ADAT format (at 44.1kHz
or 48kHz sample rates) or 4-channel audio in ADAT SMUX format (at 88.2kHz or 96kHz sample
rates).
Note that ADAT input and output is only possible when operating Titan in one of its specific
ADAT-capable modes. This is to reduce overhead on the host PC or Mac when ADAT input and
output is not required. For more information see the Unit Settings tab of the Titan Control Panel app.
It is possible to perform sample-rate conversion and word-length reduction (dithering or noise-shaping
to 16-bits) on the S/PDIF digital outputs as described in the following sections.
In normal operation, the S/PDIF digital outputs are fed directly with individual signals from the host PC
or Mac; however, it is possible to feed the outputs from local digital mixers within the Titan hardware if
desired - this is described in the Output mixers section. Outputs may also be switched to follow the
mixers of other outputs.
It is also possible to assign a level control to the S/PDIF outputs, primarily for use as a monitor
volume control - this is described in the Assignable level control section below.
Activation of output mixers and assignment of the level control are all managed in the Outputs tab of
the Titan Control Panel app.
5.1.4.1
Sample-rate converter
A two-channel sample-rate converter (SRC) can be activated in the S/PDIF output if desired. This
provides very high-quality conversion of the output signal from Titan's current sample rate to any
standard rate between 44.1kHz and 192kHz. The SRC is selected in the Unit Settings tab of the
Titan Control Panel app. Note that the SRC can be configured in the S/PDIF input, or in the S/PDIF
output, but not in both simultaneously.
When using an SRC in the S/PDIF output, it is necessary to select a synchronization source and
sample rate for the converted output. The sync source can be local, DI (the S/PDIF input) or the
Wordclock input. These settings are made in the Outputs tab of the Titan Control Panel app.
Note that presence of an SRC in the S/PDIF output is shown by an indicator beneath the digital meter
on the unit's front panel (providing that the unit's meters are in Output mode).
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Word-length
It is possible to control the word-length of the S/PDIF output using the word-length control, uppermost
in the DO1/2 strip in the Outputs tab of the Titan Control Panel app. The control operates as follows:
Setting Action
24 bit All 24 bits sent to the digital output are transmitted from the S/PDIF or AES3 output.
Channel Status is set to indicate 24 bit output. This setting can be used to pass Dolby or
DTS data to an external decoder since it leaves the audio data from the host unchanged.
Note, however, that the use of Titan's local DO mixer, or the assignable level control, or the
SRC in the digital output will prevent bit-identical data from being transmitted.
16 bit Audio data sent to the digital output is re-dithered using flat TPDF dither to produce a 16 bit
output at the S/PDIF or AES3 output. Channel Status is set to indicate 16 bit output. This
setting is not generally preferable to the SNS settings, since the noise level is not
psycho-acoustically optimized.
SNS1 Audio data sent to the digital output is noise-shaped using Prism Sound's proprietary SNS
(Super Noise Shaping) process to produce a 16 bit output at the S/PDIF or AES3 output.
SNS2 Channel Status is set to indicate 16 bit output. These settings are generally preferable to
SNS3 the 16 bit setting, since the noise level is psycho-acoustically optimized. SNS1 offers the
least optimization, but with the flattest residual noise spectrum, with optimization increasing
SNS4 up to SNS4, which offers the lowest subjective noise floor, but with significant colouration
Note that if the audio data has already been word-length-processed for 16 bit output by the DAW
software, Titan's word-length control should be set to 24 bits to prevent unwanted additional dithering.
For further discussion of dithering and noise shaping, and details of the SNS process, see the Dither
and noise-shaping section.
5.1.4.3
DO synchronization
Note that it is necessary to ensure that the sample clock of any digital audio device to which Titan's
digital outputs are connected is synchronous with Titan's own sample clock. This is usually achieved
by synchronizing the receiving equipment to Titan's S/PDIF, ADAT or Wordclock output, but can be
achieved by synchronizing Titan to the receiving device's clock or house sync (by setting DI or
Wordclock as Titan's sync source).
For more information about synchronization, see the main Synchronization section , the Clocking and
jitter section, and the section describing the Unit Settings tab of the Titan Control Panel app.
5.1.5
Output mixers and routing matrix
Titan's output mixers are high-quality, versatile stereo digital mixers available at all of Titan's outputs
(including the ADAT outputs). The signal processing in Titan's mixers is as precise and sophisticated
as in a professional digital console. All coefficients are filtered at sample-rate to minimise unwanted
quantization effects such as zipper noise.
In normal operation, Titan's output pairs are set in 'DAW' mode, i.e. they output their respective feeds
from the DAW software directly - in this case, Titan's output mixers are disabled. By selecting 'MIX'
mode for an output pair, the mixer is enabled: its inputs comprise all eight of Titan's analogue inputs,
the two-channel digital input, the ADAT inputs, plus the respective stereo feed from the DAW
software. Each input has a dedicated fader and pan pot, plus mute and solo buttons and
high-resolution level meter. Input pairs can be designated as 'stereo', wherein a single ganged fader
and balance pot are provided, plus a single mute and solo button. The stereo output also has fader,
mute button and high-resolution level meters.
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In addition, it is possible to force individual physical outputs to be fed from the mixers associated with
other outputs. This is useful, for example, in driving multiple physical stereo outputs from the same
stereo bus. Note that the routing matrix precedes the Assignable level control, so that ganged outputs
may still be individually controlled.
The output mixers are primarily intended to provide low-latency foldback or monitor mixes
incorporating Titan's audio inputs in conjunction with feeds from the DAW software - since the mix is
performed locally, the delay involved in passing live audio up to the host computer and back is
removed. However, it is also possible to configure the output mixers for general purpose use, where
inputs can be mixed to outputs without involving the Host's audio at all. Having set up such mixes
using the Titan Control Panel app, it is possible to use stand-alone mode to retain the mix features
with no computer connected.
For more information, see the Mixer tabs section of the Titan Control Panel app, and the Stability and
latency section.
5.1.6
Assignable level control
Titan's front panel has a large assignable level control. This control can be assigned individually to
any of Titan's analogue or digital (including ADAT) outputs (but excluding the headphone output which
has its own dedicated level control). Operation of the front panel control fades all assigned outputs.
The setting of the control is indicated by a halo of LEDs around the knob. The assignable level control
is primarily intended as a stereo monitor control.
Pressing the knob engages a mute mode wherein the LED halo flashes and the assigned outputs are
muted.
Assignment is via the Outputs tab of the Titan Control Panel app. In this tab, there is also an
indication of the position of the control, which can also be operated on the screen using the mouse.
5.1.7
Headphone outputs
The headphone output signal path differs from Titan's other output signal paths in a couple of
respects.
Firstly, in the Outputs tab of the Titan Control Panel app, just above the 'DAW'/'MIX' selectors is a row
of radio buttons for quickly ganging the headphone outputs onto the mixer of any other stereo output
which it is desired to monitor on the headphones, without having to use the drop list in the headphone
selector. Note that the headphone monitoring point of the outputs is before the application of the
output routing matrix and the assignable gain control (if assigned).
Second, the headphone output cannot be assigned to the assignable gain control. This is because it
already has its own dedicated volume control on the front panel.
5.1.8
Metering system
Titan's front panel meters can meter the level of either inputs or outputs as selected in the Unit
Settings tab of the Titan Control Panel app. The left-most pair of meters show the levels of the
analogue inputs (or outputs); the right-most pair show the level of the S/PDIF inputs (or outputs). The
bar-graphs change colour progressively from blue, through green to orange as signal level increases.
A red 'overload' LED is lit if the signal reaches -0.05dBFS. Each of the analogue meters has an
indicator beneath which shows when the Overkiller (progressive limiter) is active in the case of an
analogue input.
Within the Titan Control Panel app, the Inputs tab shows the levels of all of the analogue and digital
inputs (including Overkiller indicators), and the Outputs tab shows the levels of all of the analogue
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and digital outputs plus the headphones level. The Mixer tabs show levels of all inputs and the stereo
output of each mixer.
5.1.9
MDIO expansion slot
Titan incorporates Prism Sound's new MDIO expansion slot. This allows an optional expansion
module to be added, enabling Titan to connect to a host device using a different interface format from
its default USB. MDIO modules of various formats will become available in the future.
This manual does not describe fitment or operation of the MDIO modules. Please refer to the
separate MDIO Module Manual which can be found at www.prismsound.com.
When an MDIO module is fitted to Titan, it may be selected by a control in the Unit settings tab,
causing the MDIO module to become the selected connection to the host device. This is confirmed by
the Host indicator changing from green to red.
WARNING!
FITMENT AND REMOVAL OF MDIO MODULES REQUIRES REMOVAL OF THE
UNIT'S TOP COVER, WHICH PRESENTS A RISK OF ELECTRIC SHOCK.
REMOVAL OF THE TOP COVER MUST ONLY BE CARRIED OUT WITH THE
POWER SOURCE DISCONNECTED FROM THE UNIT AND BY QUALIFIED
SERVICE PERSONNEL.
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Synchronization
This section seeks to clarify some potentially confusing issues to do with synchronization. Note that
use of multiple Titan units on a single host computer is not currently supported.
Sync sources, masters and slaves
Titan behaves as a class compliant UAC2 (USB Audio Class 2.0) device, and operates in
asynchronous mode. This means that the sample clock is always controlled from within the Titan unit,
and is NEVER locked to the USB bus or the host computer.
Where Titan is generating its sample clock from its internal reference clock (local mode) it is
considered to be the clock master, and its front panel 'master' LED is lit. When it is locked to an
external sync source (Wordclock, DI or ADAT) it is considered to be a clock slave, and its front panel
'master' LED is not lit. Where an external sync source has been selected but is either invalid or is
operating at a different frequency from the nominated sample rate, the 'master' LED flashes and the
internal (local) reference is used instead. An exception to this is that during stand-alone operation, the
sample rate automatically follows the frequency of the selected sync source so long as it is valid. For
more information see the Unit settings and Stand-alone operation sections.
Every input and output channel must operate at a common sample rate and is locked to a common
synchronization source. An exception to this is when a sample rate converter (SRC) is configured in
Titan's digital input or output. In the former case, the SRC simply converts any incoming digital signal
of whatever sample rate to the sample rate of the Titan unit. If the SRC is in the digital output, it is
necessary to specify what the output sample rate must be; furthermore, it may be necessary to lock
the output rate to an arbitrary external reference. Titan allows for this; as described in the Outputs tab
section of the Titan Control Panel app chapter.
Wordclock output
As well as outputting a clock at the selected sample rate, Titan's Wordclock output can be configured
to produce a '256x clock' (a clock at 256x the selected sample rate, e.g. a 'superclock') or a
'Baseclock' (44.1kHz if the sample rate is a 44.1kHz multiple, or 48kHz if the sample rate is a 48kHz
multiple).
TAKE NOTE
It may not be possible to change the sample rate whilst any of Titan's ports are in use by an
audio application (e.g. a DAW). In this case it is necessary to disconnect the ports from the
application before changing the sample rate, or (where possible) to change the rate from
within the application.
If an external sync source such as DI or Wordclock is selected, but is either absent or at a
different rate from the selected sample rate, the unit reverts to local (internal) sync at the
selected sample rate. If the reference is later applied at the appropriate rate, audio is
re-enabled. Note that during Stand-alone operation an external sync source is allowed to
control the unit's sample rate.
5.3
Front panel
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Titan's front panel contains a limited number of physical controls and indicators. A greater degree of
control is available using the Titan Control Panel app software provided. The front panel also
contains the instrument input and headphone output jacks.
From left to right:
· Instrument input jacks 1&2: mono unbalanced jacks, high impedance, with finely adjustable gain
control. See Analogue inputs. Note that Titan 1 has only one instrument input.
· Meter panel: see below.
· Assignable level control: Volume knob which can be assigned to any of Titan's outputs (except for
the headphone output), as required. This is primarily intended as a monitor volume control for
stereo monitoring. Note that pressing the knob mutes any outputs assigned to the control; this
state is indicated by the LED halo around the knob flashing.
· Headphone jacks 1&2: each with its own volume control.
· Standby button: puts the unit into a low-power standby state. Note that the USB interface is still
active in standby mode, so the Titan unit can still be recognised by the host, although its inputs and
outputs are inactive. The LED in the standby button flashes to identify the unit in multi-unit setups
when the 'Identify' button in the Control Panel app is clicked. Entering standby mode causes Titan
to retain its current software control settings in flash, for example for use in stand-alone mode.
Meter panel
The meter panel contains metering for the analogue input and output channels and the S/PDIF input
and output channels. It also contains the input selection indicators and Overkiller activity indicators for
all the analogue inputs, unlock and SRC indicators for the S/PDIF input, and an SRC indicator for the
S/PDIF output.
From left to right:
· Input selection indicators: these indicators show the analogue input selections; green for line, or
pink for mic or blue for instrument preamplifiers. The mic selection indicators change from pink to
red to indicate that phantom power is switched on. See Analogue inputs.
· Host indicator: this indicator is normally lit green, to show that Titan is connected to the host
computer via the USB interface; however, when lit red, it indicates that the unit is using the MDIO
(multi-channel digital IO) expansion module to connect to a non-USB host, as described in the
MDIO expansion slot section. Note that future firmware/software may allow host connection via
Ethernet, in which state the Host indicator will be lit orange.
· Master indicator: this is lit when the device is set to local (internal) sample clock, and off when
locked to an external sync source; it flashes when local sync has over-ridden an invalid external
sync source selection. For more information see the Synchronization section.
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· Meter input/output indicator: shows whether the bar-graph meters are assigned to the analogue and
S/PDIF inputs (IP indicator is lit), or to the analogue and S/PDIF outputs (OP indicator is lit). This is
selected in the Titan Control Panel app. See the Metering system section for more details.
· Overkiller indicators: indicate that the Overkiller progressive limiter is operating in that channel.
Note that the indication is dynamic, and shows when the Overkiller is actually limiting, and not
simply that it is enabled. Note that the Overkiller indicators are only active when the meters are in
input mode.
· DI unlock indicator: indicates that the S/PDIF input is unlocked, i.e. no S/PDIF carrier is recognised.
Only active when the meters are in input mode.
· SRC indicator: shows that the SRC (sample-rate converter) is configured in the S/PDIF input (when
the meters are in input mode) or is configured in the S/PDIF output (when the meters are in output
mode).
5.4
Rear panel
Titan's rear panel contains all Titan's connections, except for the instrument inputs and headphone
output, which are on the front panel.
From left to right (viewed from rear):
· 6A IEC inlet (regional power cord supplied): adjacent is the mains fuse holder.
· RJ45 100Mbps Ethernet port: reserved for future use.
· USB 2.0 device port for connection to host computer (cable supplied).
· Wordclock output and input BNC sockets: the Wordclock output can supply base-clock or 256x
clock if required. See the Synchronization section.
· MDIO module slot: allows connection to a non-USB host via an optional MDIO (multi-channel IO)
expansion module, as described in the MDIO expansion slot section.
· TOSLINK output and input: can be used for S/PDIF (up to 192kHz sample rate) or ADAT
(44.1kHz/48kHz, or 88.2kHz/96kHz in SMUX mode). See Digital inputs and Digital outputs.
· S/PDIF output and input RCA sockets: these can also be operated as AES3 interfaces (RCA-XLR
and XLR-RCA adapter cables supplied). See Digital inputs and Digital outputs.
· Line output TRS jacks 1-8: switchable +4dBu/-10dBV level, can operate in balanced or unbalanced
mode. See Analogue outputs.
· Line input TRS jacks 5-8: switchable +4dBu/-10dBV level, can operate in balanced or unbalanced
mode. See Analogue inputs.
· Mic/Line input Combos 1-4: for microphones, with 10dB to 65dB finely-adjustable gain, switchable 20dB pad and switchable phantom power. See Analogue inputs.
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Fuses and ratings
TO PREVENT SHOCK HAZARD, THE Titan HARDWARE SHOULD ONLY BE
OPENED BY QUALIFIED PERSONNEL. REMOVE THE POWER LEAD FROM THE
UNIT BEFORE REMOVING THE TOP COVER.
Fuse locations and ratings are as follows:
FUNCTION
Mains
LOCATION
Rear panel
TYPE
500mA(T), 20mm, glass
Note that no fuses or any other user-serviceable parts or options are located inside the Titan
unit.
5.5
Stand-alone operation
It is possible to operate Titan without a connection to a host computer. This is done by setting up the
unit as required using the Titan Control Panel app whilst it is connected to a host computer via its
USB interface, then placing the unit in standby by pressing the standby button, before disconnecting
the unit from the host and power source. When the unit is re-powered, and detects that no USB
connection is active, it reloads the settings which were previously stored.
Since all of the outputs have optional mixers within the Titan hardware whose inputs include all of
Titan's input connectors, it is possible, for example, to connect the digital input pair to one or more
analogue output pairs, and to connect the analogue input pairs to the digital output pair. The
synchronization source and sample rate can be set in the usual way. Thus stand-alone mode can be
used to configure a stand-alone D/A converter and A/D converter, with static mixing if required.
NOTE: If, during stand-alone operation, Titan is set to use an external synchronization source,
i.e. DI, Wordclock or ADAT (only available in ADAT modes), then the sample rate is
automatically changed to follow the sample rate of the external synchronization source. If the
designated synchronization source is not connected, the sample rate reverts to local sync at
the selected sample rate.
5.6
Rack mounting
Titan is supplied configured for table-top operation, with rubber feet attached and no rack-mount ears
fitted.
To convert for rack-mounting: First fit the rack-mount ears by removing the front four screws from
each side of the unit, using the hex key provided; then replace the same screws to retain the rack
ears. If necessary, the rubber feet can be removed by withdrawing the plastic centre-hub of each foot
a little way prior to pulling the whole foot out. The hub can be initially raised with a small flat-bladed
screwdriver. Retain the feet for later use.
If Titan units are rack mounted, an empty 1U gap should be left above each Titan to ensure effective
cooling.
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Titan software
This section describes the software supplied with Titan.
6.1
Titan Control Panel app
The Titan Control Panel app is a program which can be used to adjust Titan's settings and view its
metering and status indicators, from the screen of the Mac or PC.
Whilst Titan can be controlled in a limited way from within the Mac or Windows operating system, or
by some audio application programs, most of its detailed features can only be accessed using the
Titan Control Panel app.
Accessing the Titan Control Panel app
The Titan Control Panel app can be run directly like any other Mac or Windows program, or it can be
accessed from the operating system itself, from the "Sound and Audio devices" dialogue in the
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Windows' Control Panel (or from the Device Manager) or from the Audio MIDI Setup in Mac OS X.
Some audio applications also allow guided access to the Titan Control Panel app.
Operating the Titan Control Panel app
The Titan Control Panel app is a variable-size dialogue box which can be activated and 'put away' like
any other Mac or Windows application. When active, it cannot be resized. The upper part of the
Control Panel contains Unit settings, and beneath are a stack of 'tabs' allowing context-switching of
the bulk of the user-interface area.
The Inputs tab contains everything to do with setting up analogue and digital inputs, the Outputs tab
similarly for outputs. A row of Mixer tabs provide access to the low-latency built-in mixers for each
output pair.
Where more than one Titan unit is connected, a separate Titan Control Panel controls each
connected unit (see the section on Operating multiple units). If no Titan units are connected, the
Control Panel is replaced by a small dialogue box which reports this. Note that operation of more than
one Titan unit on a single host computer is not currently supported.
6.1.1
Unit settings
The upper area of the Titan Control Panel contains the main settings for the Titan unit.
The upper area also contains buttons for loading and saving Titan configurations, and for accessing
the on-line help.
The Titan model and serial number are displayed at the top of the Unit settings area. Note that the
currently-installed firmware version of the Titan unit can be displayed by hovering the mouse cursor
over this text.
The Sample Rate and Sync Source controls allow the unit's reference sample rate and
synchronization source to be selected. For more details, see the Synchronization section.
NOTE: If an external sync source such as DI or Wordclock is selected, but is either absent or
at a different rate from the selected sample rate, the unit reverts to local (internal) sync at the
selected sample rate. If the reference is later applied at the appropriate rate, audio is
re-enabled. Note that during Stand-alone operation an external sync source is allowed to
control the unit's sample rate.
NOTE: It may not be possible to change the sample rate whilst any of Titan's ports are in use
by an audio application (e.g. a DAW). In this case it is necessary to disconnect the ports from
the application before changing the sample rate, or (where possible) to change the rate from
within the application.
A two-channel sample-rate converter (SRC) can be configured in the S/PDIF input path, or in the
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S/PDIF output path, or can be disabled, using the SRC control.
The ADAT mode control selects the number of supported ADAT inputs and outputs as follows:
ADAT mode
No ADAT
ADAT4
ADAT8
ADAT inputs
None
Four channels
Eight channels
ADAT outputs
None
Four channels
Eight channels
Sample rates available
44.1kHz - 192kHz
44.1kHz - 96kHz
44.1kHz, 48kHz
In ADAT4 mode at sample rates of 88.2kHz and 96kHz, SMUX mode is used. By default, ADAT
ports are disabled to ease load on the host computer. For more information, see the Digital inputs
and Digital outputs sections.
NOTE: Changing the ADAT mode causes changes in the number of input and output channels
reported to the host computer by Titan. It is therefore advisable to close your DAW
application before changing the ADAT mode, and to restart it again afterwards, in order to
ensure reliable operation.
The FP Meters control allows the front panel meters to be switched between the analogue and
S/PDIF inputs, and the analogue and S/PDIF outputs. For more information, see the Metering system
description.
The Clock Out control can be used to cause the Wordclock output to produce Baseclock or 256x
clock instead of Wordclock if required. For more details, see the Synchronization section.
The LED Level control allows the brightness of the LEDs on Titan's front panel to be adjusted to suit
ambient lighting conditions.
In Windows ASIO systems, the audio delay through the input and output buffers can be controlled
with the Buffer control. The buffer time is entered in samples. The buffer time may be automatically
adjusted by the software when the sample rate is changed. In general, it is better to keep the buffer
time quite long. This reduces the risk of audio glitches, as described in the Stability and latency
section. Titan's low-latency on-board foldback mixing facility reduces the need for the low latency in
the driver. Note that the WDM buffer length is set by Windows; in Mac systems, buffer latency control
is handled by OS X.
Below the Unit Selector is the Identify button. This can be latched on or off. In the on state (high-lit
red) the LED in the standby switch of the associated unit flashes. This allows identification of each
unit in a multi-unit system (if supported).
Load, Save and Help buttons
The green Help button ('?') opens the online version of this manual in a browser window.
The red Save and the orange Load buttons save and load Titan settings to and from disk.
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Inputs tab
The Inputs tab contains the controls and status indicators for all functions of the analogue inputs and
S/PDIF inputs as described in the hardware section. In ADAT modes, the status of the ADAT/SMUX
inputs is also displayed here.
The mode of each analogue input is indicated by the coloured tile at the top of the strip. Clicking on
the tile in MIC or PAD (microphone preamp with -20dB pad) modes allows the pad to be selected or
deselected. Note that the input mode selection is made automatically according to which input
connectors are sensed. Line input mode, indicated by the green 'LINE' legend, is selected whenever
a jack is plugged into the line input. Instrument mode, indicated by the blue 'INST' legend, is selected
in an instrument jack (but no line jack) is detected. Microphone mode, indicated by a pink 'MIC' or
'PAD' legend, is selected if neither instrument or line jack is detected. Inputs 5-8 are fixed in line
mode for Titan.
Line input sensitivity is switched between +4dBu and -10dBV nominal by the '+4/-10' radio buttons,
whereas microphone and instrument input gains are adjusted in 1dB steps by the slider controls, and
indicated by the number beneath, which can also be directly entered if required.
Overkiller progressive limiters, phase-reversal and high-pass filters are selectable for each analogue
input. Mic inputs have +48V phantom power switchable per-channel. Analogue inputs 1 and 2 also
have an RIAA de-emphasis filter selectable as an alternative to the high-pass filter, allowing them to
be used with vinyl decks. MS matrixing is available on all channel pairs, allowing use of mid-side
microphone configurations.
The DI strip can be switched between RCA and TOSLINK S/PDIF inputs, and ULOK and ASNC
indicators are provided. ULOK (unlock) is lit when no S/PDIF carrier is detected at the selected input;
ASNC (asynchronous) is lit when the incoming carrier is not locked to Titan's selected sync source.
In ADAT modes, ULOK and ASNC indicators are also provided for the ADAT/SMUX inputs.
All inputs have high-resolution peak metering, with overload indication 0.05dB below clipping; the
analogue input meters also have Overkiller-active indicators which light dynamically when the
Overkillers are limiting.
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Outputs tab
The Outputs tab contains the controls and status indicators for all functions of the analogue outputs
and S/PDIF outputs as described in the hardware section. In ADAT modes, the status of the
ADAT/SMUX outputs is also displayed here.
Line output level is switched between +4dBu and -10dBV nominal by the '+4/-10' radio buttons.
The stereo digital output has a versatile word-length control using TPDF dither or Prism Sound SNS
(Super Noise Shaping), and the RCA connector can be switched to operate as either S/PDIF or AES3
as required. If the sample rate converter (SRC) is configured in the digital output, a separate sync
source and sample rate can be selected.
An assignable level control is available, for use as a monitor volume control, which can be assigned
to any desired outputs using the row of 'VOL' buttons. The volume control can be adjusted using the
mouse, as well as with the front-panel knob. There is also a mute button (whose function is also
available by pressing the volume knob on the Titan front panel) and a numerical readout/setting box.
Note that changes to the assignment of the level control can be prevented by engaging the lock
button (marked with a key symbol) just above the level control. When engaged (red) the lock button
prevents changes to the level control assignment in order to avoid accidental full-level output.
Below each stereo output strip is a drop-list control allowing each output pair to be fed either directly
from the workstation ('DAW') or from a dedicated low-latency foldback mixer ('Mixer'), or from the
mixer associated with any other output pair. Each stereo mixer can mix any of Titan's analogue,
digital and ADAT/SMUX inputs to the output pair, along with the DAW feed, as described in the
following section. Above these output mode drop-lists are a row of dedicated radio buttons which
cause the headphone output to be routed from the mixer associated with that output pair directly.
Note that these radio buttons are additive, i.e. multiple output pairs can be selected to be mixed to the
headphone output.
All outputs have high-resolution peak metering, with overload indication 0.05dB below clipping.
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Mixer tabs
The Mixer tabs control the low-latency foldback mixers which are available for every output pair,
including the analogue, digital, headphone and ADAT/SMUX outputs. Note that the ADAT/SMUX
mixer tabs only appear for ADAT/SMUX channel pairs which exist in the current ADAT mode.
Although the mixer tabs are always available for every output pair, it should be noted that the mixers
may be 'defeated' for each output by setting that output to follow its dedicated DAW feed, or by
setting it to be routed from the output of another mixer. This is under the control of drop-list controls
on the Outputs tab, which are duplicated in the output strip of each respective mixer.
Each input channel has a fader, a high-resolution peak meter, with overload indication 0.05dB below
clipping, plus mute and solo buttons and a pan-pot. By engaging the 'Stereo' button beneath an input
pair, the pair is controlled by a single stereo fader, mute button and solo button, and the pan-pots are
replaced by a single balance control. The DAW contribution and output strip are always in stereo
mode.
Note that if the mixer tab is not active (because the output pair is in 'DAW' mode or is routed from the
output of another mixer), the mixer controls are still available but the output mode control in the output
strip is highlighted in red.
For more information, see Output mixers in the hardware section.
6.2
Titan drivers
For Windows systems, Titan is supplied with a driver which provides ASIO and WDM audio
connectivity to the device. This driver is installed when the initial installation is performed. Thereafter,
this connectivity is permanently available. It is not necessary to run the Titan Control Panel app for
applications to be able to use Titan; however, the app is needed if any but the most basic control of
Titan's functions is required.
The same is true in Mac systems, except that no driver is installed because OS X is able to operate
Titan directly as a USB Audio Device Class 2.0 device to obtain Core Audio functionality. However,
whilst some degree of control is possible from the Mac's Audio MIDI Setup window, the Titan Control
Panel app must still be run to control the majority of the unit's functions.
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7
Technical topics
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Technical topics
The following sections contain detailed discussions of various relevant technical issues. The content
of these sections is not required to operate Titan, but is provided merely as background information.
7.1
Stability and latency
Ever since audio production has found its way inside the computer, new problems concerning issues
of stability and latency have arisen.
Pre-computer digital audio gear introduced the concept of delays through devices, which hadn't
usually been the case with analogue equipment. This was an inevitable consequence of sampling the
audio, and passing the samples through multiple layers of buffering during conversion, processing
and interfacing operations. However, the 'latency' (buffer delay) was generally quite short and didn't
usually cause problems even in delay-sensitive applications such as live sound or over-dubbing.
Reliable operation was generally guaranteed, since the digital devices were essentially 'sausage
machines' performing nothing but the same limited series of operations repeatedly.
When general-purpose computers began to be used for audio production, problems with latency and
stability suddenly had to be addressed. The reason is that computers are always busy doing other
things than processing audio, even in situations where the operator is only interested in performing
that dedicated task. Because of this, the computer generally accumulates a large buffer of incoming
audio samples, which are then processed whilst a new buffer is being collected. Even though the
required processing can (hopefully) be accomplished faster than real-time (i.e. the sample
processing rate is faster than the sample rate), there is always the possibility that the computer may
be called upon to interrupt its processing of the audio in order to deal with some other essential
routine task, such as maintaining screen graphics, moving data on and off disc, servicing other
programs etc. In non-optimized systems, tasks such as collecting emails, virus-checking and
countless low-importance system operations can interrupt audio processing. Without the
accumulation of sample buffers, any interruption taking longer than about one sample period (1/fs)
would cause incoming audio samples to be missed, resulting in disruption of the audio signal. Nearly
every kind of interruption is long enough to do this. However, with a large enough buffer, the
interruptions don't cause audio to be disrupted so long as the computer has enough time available
during the buffer period to process the entire buffer. This problem doesn't only happen for incoming
samples: audio outputs from the computer must likewise be buffered so that a continuous output
stream can be maintained even when the processor is called away for a while.
Why is this a problem? First of all, the amount of latency required in order for a particular computer
with a particular audio processing and non-audio workload not to suffer audio disruptions can be
problematically large. This is particularly the case in live sound and over-dubbing situations where the
delay between the computer's input and output has to be essentially imperceptible. This is often
difficult or impossible to achieve, unless the computer has a powerful processor, a lot of memory, a
heavily audio-optimized operating system workload, an efficiently written audio processing program,
and not too many audio channels, not too much audio processing complexity, and not too high a
sample rate. The operator merely has to make sure that all these conditions are met, and all will be
well!
But how do you do that? Even if we worry only about the computer and operating system themselves,
the duration and frequency of interruptions is very non-deterministic: something can happen very
infrequently which causes a huge interruption. This might not be a problem: you can always run that
track again (assuming you noticed the glitch) - but what if you're recording an important one-off live
event? Even worse, the onset of trouble is greatly affected by audio factors such as number of
tracks, sample rate, how many EQs are in use, etc. This makes the onset of instability even harder to
predict reliably.
On the other hand, situations where latency is critical are relatively few, so it is normally OK to operate
generous buffers - such as in the live recording example.
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In the case of Titan, problems of latency and stability are improved by a couple of useful features:
First of all, the operator can control the buffer delays within the Mac and Windows drivers directly,
irrespective of what buffering is employed by the user's particular audio software. It is generally
recommended that these buffer delays are set long, in order to provide best stability. However, for
the user with a powerful and tightly-optimized setup, who has contained audio processing tasks and
needs low latency, the buffer delay can be minimized. For more information, see the Unit settings
section.
For foldback and over-dubbing situations, all of Titan's outputs (analogue 1-4, S/PDIF, ADAT, DO,
and headphone outputs) have a comprehensive mixer capability which can mix any of the unit's
inputs with each output's computer feed in order to build a dedicated monitor mix with extremely low
latency. Incoming audio to the mix doesn't have to go in and out of the computer at all - the mix is
handled within the Titan hardware itself. For more information, see the Outputs tab and Mixer tabs
sections.
7.2
Clocking and jitter
Good clock stability is probably the single most important issue separating good-quality analogue
interfaces from the rest. With the linearity of modern A/D and D/A converter chips beginning to rival
and exceed the performance of the best analogue circuits, digital recordings would already be ‘
beyond reproach’ if clock stability did not so often degrade their potential quality.
Why is good clock stability so rare? Probably because most conversion equipment has to
compromise between clock stability, operational requirements and cost. The ideal clock system in an
A/D or D/A converter would be ultimately stable, i.e. would exhibit no jitter (frequency variations) at the
point of conversion, whether operating from an internal clock or from an external synchronization
reference of any format and at any sample rate. But this is a very tall order for circuit designers,
especially if they are on a budget.
Why are good clocks so rare?
Most analogue interfaces can provide workmanlike performance when internally clocked, since this is
only a matter of providing a stable clock oscillator (or range of oscillators) at a fixed frequency (or
frequencies) – although even this is not always well-executed. The real problem is that in many
installations the analogue interfaces can almost never operate from their own internal clocks since
they must be slaved to an external reference sync, or maybe to a clock from a host computer.
The externally-clocked design challenge has traditionally been a trade-off since the more stable a
clock oscillator is, the less is its range of frequency adjustment: but we would ideally like an oscillator
which can operate over a wide range of sample rates, perhaps from <44.1kHz to >48kHz, plus
multiples thereof. But such an oscillator would inevitably have poor stability – at least in terms of the
stringent requirements for high-quality audio conversion. On the other hand, if we limit the range of
rates at which the oscillator needs to operate to small ‘islands’ around the standard sample rates we
could use a bank of oscillators, selecting the appropriate oscillator according to our desired sample
rate. But this is expensive and, in any case, the 'pull-range' of an ordinary quartz crystal oscillator is
still generally insufficient to meet the tolerance demands of the digital audio interfacing standards.
As well as a very stable clock oscillator, a good sounding converter must have a PLL (phase-locked
loop) with a loop-filter which steeply attenuates incoming reference jitter towards higher frequencies.
Unfortunately, even if sourcing equipment provides a reference clock with low jitter, cabling always
adds unacceptable amounts, especially poor quality or high-capacitance cable, which results directly
in sampling jitter in the analogue interface if jitter-filtering is inadequate.
Prism Sound's unique CleverClox technology breaks these traditional constraints, allowing a low jitter
clock to be re-created from any reference sync, no matter how much jitter it has and no matter what
its frequency.
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But why is clock jitter so important?
Analysis of sampling jitter
Analysis of sampling jitter (small variations in the sampling intervals of an A/D or D/A converter)
shows that it produces a similar effect to phase modulation, where distortion components appear as ‘
sidebands’ spaced away from the frequency of a converted tone by the frequency of the jitter itself.
These components get louder as the amount of jitter increases, but also as the frequency of the
converted tone increases. So sampling jitter produces distortions which should sound much worse
than conventional analogue harmonic distortions, since the spurious components appear at
aharmonic frequencies. High audio frequencies should suffer worse distortion than low frequencies.
For low-frequency jitter, the resulting distortion sidebands appear close in frequency to the audio
signals which produce them – this should mean that they are ‘masked’ from our hearing by the same
psycho-acoustic phenomenon upon which are based sub-band (perceptual) coding schemes such as
MPEG. This is fortunate, since it is quite difficult for a PLL to remove jitter to a good degree even at
moderate frequencies, but for very low frequencies it would be very difficult indeed.
The graph below shows the effects of 'JTEST', a special test stimulus to expose jitter susceptibility of
D/A converters. JTEST is basically an fs/4 tone (12kHz at fs=48kHz) which is specially coded to
cause an AES3 or S/PDIF carrier transmitted over a lossy cable to become very jittery by the time it
reaches the receiving D/A converter. The jitter produced has regular frequency components fs/96
apart (500Hz at fs=48kHz). The quality of the D/A converter's jitter rejection is shown by the degree
to which it suppresses the resulting 500Hz-spaced side-tones. In the example below, the upper trace
shows the poor jitter rejection of 'conventional' D/A converter design, where the conversion clock is
derived directly from the AES3 or S/PDIF receiving chip, without any further jitter filtering. Remember
that none of these side-tones is present in the digital audio signal - they are caused only by jitter. The
lower trace shows almost complete jitter rejection across the band by the CleverClox process in Titan.
Listening experience
In practice, it seems that the benefits of careful clock design are very apparent in listening tests. On
the other hand, it can sometimes be difficult to expose the shortcomings of converters with poor
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clocks, because these units often have other analogue problems whose severity might obscure
jitter-related effects.
In general, some of the widely-noted effects of sampling jitter are not surprising – for example the
muddying of brass, strings and high-frequency percussion and the loss of stereo (or multi-channel)
imaging. These are well explained by the worse distortions which result in the lab at loud, high
frequencies, and the way that sampling jitter produces quiet, aharmonic components, perhaps only
subliminally perceptible, which blur our impression of the ambience which creates a soundstage.
Other effects are harder to explain – for example there is wide observation that large amounts of
sampling jitter can take the edge off extreme bass rendition. Such reports are probably too
widespread to be ignored, but defy explanation within current theory.
Titan and CleverClox
Titan is designed to source clocks which are as stable and accurate as possible, and also with the
aim of being insensitive to the quality of incoming clocks. It is designed to remove jitter from any
selected reference sync source before it is used as a conversion timebase, so as to eliminate any
audible effects of sampling jitter, whatever sync source is used.
Titan does this with the help of Prism Sound's unique CleverClox clock technology, which removes
the jitter from any selected clock source down to sub-sonic frequencies, without the need for a
narrow-band quartz VCO. CleverClox can adapt to any reference, irrespective of frequency, and
regardless of how much jitter it has, derives an ultra-stable conversion timebase.
7.3
Dither and noise-shaping
Titan can dither or noise-shape its digital output to produce high-quality 16 bit output (for, say, a CD
master) from 20 bit or 24 bit recordings. This section discusses the principles and choices involved in
word-length reduction.
Truncation and dithering
There are many points in a digital audio signal path where precision can be lost. For example, in a
digital transfer from 24-bits to 16-bits, or in an analogue to digital conversion. In this situation it is not
sufficient just to discard low-order bits – this causes truncation distortion, characterised by aharmonic
frequency components and unnatural, harsh decays.
Instead, it is preferable to use some sort of ‘dithering’ process, whereby the truncation process is
linearized by modulating the signal prior to the truncation, usually by the addition of a small amount of
noise. By adding a random element to the truncation decision, small components as far as 30dB
below the noise floor can be accurately represented, and an analogue-like low-signal performance
can be realised. This is achieved at the expense of slightly raising of the noise floor, although with
some dithering schemes such as noise-shaping, linearization can be achieved with no noticeable
increase in noise.
How can dithering allow information to be preserved below the least-significant bit? It seems
impossible. Consider a simple example where the audio samples are numbers between one and six,
and we are going to ‘truncate’ them (i.e. reduce their resolution) so that numbers from one to three
become zero, and those from four to six become one. Clearly much information will be lost, and all
excursions of the signal between one and three and between four and six will not affect the output at
all. But if we throw a die for each sample, add the number of spots to that sample, and translate
totals of six and below to zero and totals of seven and above to one, we have a simple dithering
scheme. Input samples of three will be more likely to result in outputs of one than will inputs of one.
The throw of the die is our dither noise. Since all the faces of the die have an equal chance of
occurring, this is known as ‘rectangular probability distribution function’ (RPDF) dither, which in fact
does not produce perfect linearization. We actually use ‘triangular probability distribution function’
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(TPDF) dither, which is like throwing two dice with a resultant increase in the probability of medium
sized numbers – totals of two and twelve occur much less often than seven.
Noise shaping
It is possible to reduce the subjective effect of the added dither noise by either using spectrally
weighted ('‘blue'’) dither noise, which is quieter in the more sensitive registers of the ear, or by an
even more effective technique called 'noise shaping’.
Noise shaping is just like conventional dithering, except that the error signal generated when the
unwanted low-order bits are discarded is filtered and subtracted from the input signal. You can’t get
something for nothing – the error cannot be simply cancelled out, because we already know that the
output hasn’t got enough bits to precisely represent the input. But by choosing an appropriate shape
for the error filter, we can force the dither noise / error signal to adopt the desired shape in the
frequency domain – we usually choose a shape which tracks the low-field perception threshold of the
human ear against frequency. As can be seen from the plots below, this has the effect of actually
lowering the noise floor in the more sensitive frequency bands when compared to the flat dither case.
The theory of noise shaping has been around for a long time – certainly since well before DSP in
real-time was feasible for audio signals. It has applications in many signal processing and data
conversion applications outside audio. It has been well researched, and is not in the least bit
mysterious. ‘Proprietary’ word-length reduction algorithms are generally conventional noise shapers.
Assuming that the basic implementation and dither levels are correct, the only significant freedoms
available to the designer are to choose the actual shape of the noise floor, and to decide how to adapt
this (if at all) to different sample rates.
Prism Sound SNS (Super Noise Shaping)
Titan provides a comprehensive choice of dithering and noise-shaping processes. These comprise ‘
flat’ dithering, plus a selection of four Prism Sound ‘SNS’ (‘Super Noise Shaping’) algorithms. All
produce high-quality 16 bit output: the choice of which one to use is purely subjective. The four SNS
algorithms are designated SNS1 to SNS4, in increasing order of the degree of shaping. The spectra
of the four SNS algorithms are shown below. Note that, unlike some noise shaping algorithms, SNS
spectra are adjusted automatically to provide optimum subjective advantage at each different sample
rate. The spectra are shown below for 16-bit output, at 44.1kHz, 48kHz and 96kHz sample rates.
SNS1 provides the smallest subjective noise advantage, but only applies limited
noise-lift at quite high frequencies. In many applications, particularly those where
the program material is already quite noisy, this type of shaper is preferred.
SNS2 is a happy medium. It provides a good amount of subjective lowering of the
noise floor, but with addition of only moderate amounts of high-frequency noise. It
also has the advantage that the noise floor remains subjectively white, even when
artificially amplified. In the fifteen years since Prism Sound first developed the four
SNS curves, SNS2 has been the most widely preferred.
SNS3 and SNS4 are ‘optimal’ shaper designs – their shaping is quite extreme in
order to get the maximum theoretical subjective improvement in noise
performance based on an average human low-field sensitivity curve. This results
in the addition of larger amounts of high-frequency noise. These shapers are only
really useful if the original recording has a very low noise floor.
It is difficult to assess the difference in sound between different noise shapers for any given program
material, since their effects are at very low amplitudes (the 0dB line on the plots below represents flat
dither with an rms noise amplitude of about –93.4dBFS). It is tempting to audition noise shapers by
using a low signal level and boosting the shaper output by tens of dBs in the digital domain prior to
monitoring. Using this method it is easy to hear that the noise floor of more extreme shapers is
clearly not white – switching, say, from SNS1 to SNS4 sounds like shhhhh..ssssss as the noise is
shifted towards the higher frequencies. However, this is not really a meaningful test since the
sensitivity of the ear at different frequencies is very dependent on level, and the design of the more
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extreme shapers is in any case intended to render the noise floor completely inaudible at normal
listening levels. Ultimately, the only ‘right’ choice of noise shaper is the one which sounds best for the
material. SNS2 is a good starting point for most situations.
The Prism Sound SNS logo shown above is found on many of the world’s finest CDs, and is
recognised as a standard of technical excellence. The logo, and accompanying sleeve note, is
available by contacting [email protected].
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Analogue interconnections
To maintain the high sound quality of Titan, it is important to follow some basic guidelines when
making analogue connections to the unit. This section discusses some things to watch out for.
Cable quality
Use of good-quality, heavy duty audio cables is recommended. For microphone use, quad-twisted
cables may give best results. Cables with heavy screens are recommended, especially for
unbalanced use. Owing to mechanical differences between connectors from different manufacturers,
it is advised to use cables with identifiable connectors from reputable manufacturers. This is
especially true for jacks, where unreliable tip connection can occur owing to the slightly
non-conforming shape of some manufacturers' parts. Neutrik connectors are used in Titan, and
these are recommended to ensure reliably-mating cables.
Balanced versus unbalanced connections
Where possible, balanced interconnections should be used, since the audio signal is represented as
a voltage difference between two dedicated conductors (neither of which is ground-coupled), which
are usually closely-twisted to ensure that any interference pickup is cancelled out. In unbalanced
connections, the signal is represented as a voltage difference between a single signal conductor and
an accompanying ground conductor. Where dynamic ground-potential differences exist between the
source equipment and the receiving equipment, this difference is effectively added to the unbalanced
audio signal.
This effect has long been familiar in audio systems as 'hum loops', where the variation in ground
potential occurred at line-frequency, and was developed by the flow of line-frequency currents to
linear power supplies. Hum loops were usually resolved by either steering the currents along
non-critical routes by re-arranging the topology of the system ground interconnections, or by
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mass-interconnection the system grounds using heavy gauge cable so as to minimize the hum
voltage resulting from the current.
Obviously many items of analogue audio equipment only have unbalanced connections; this is
especially true of consumer equipment, which is often used for monitoring even in professional
studios. If you must use unbalanced connections, keep them as short as possible and use
good-quality cables with substantial screens. If you have a choice, keep the signal level as high as
possible on the interconnection, since this will make any interference proportionally less noticeable.
Instrument connections are often particularly vulnerable to hum and other interference, since they are
usually unbalanced and low-level, and frequently employ a long cable not selected for its
interference-immunity qualities. Also, the source impedance is often high, making the connection
particularly vulnerable to interference.
Some digital audio and computer equipment with switched-mode power supplies can cause
particularly troublesome interference problems, especially for low-level, unbalanced signals. This is
discussed in the following section.
Interference
The increasing use of low-cost digital equipment and computers in the audio production process
results in various potential problems for the remaining analogue devices. It is well-known that the
hostile power and EMC environment inside a typical computer is likely to be the limiting factor
governing the audio quality of an internal analogue sound card. A solution to this is the use of external
'sound cards', such as Titan, with their own enclosures and power supplies allowing adequate space,
power and electromagnetic peace and quiet for the well-being of studio-quality analogue circuits.
However, even the sound quality of external devices can be compromised by the proximity of some
types of digital equipment. Many low-cost switched-mode power supplies emit interference which can
compromise system audio quality even at a distance. The hostile mechanism is usually 'conducted
interference', wherein the high-speed switching action of the power converter results in voltage and
current transients being conducted back down their power cords. If the equipment is connected to
mains safety-ground, transients can also be conducted down the ground connection. Radiated
emissions (airborne radio interference) can also be a problem, but it is less common that this will
have such a serious effect on audio quality.
Conducted power-line interference can cause problems in analogue equipment within the installation
if its own power supply allows the transients to pass through to the audio circuits. However,
conducted ground interference can be even worse since, if the ground connection of the analogue
equipment is modulated by switching interference, there is nothing that the designer of the equipment
can do to combat it.
How much any conducted ground interference affects audio quality depends on many factors, mostly
to do with how the various analogue boxes in the system are interconnected and grounded. Where
possible, high-level balanced connections should be used, just as in the case of hum-loops as
discussed in the previous section.
Where ground-potential variations are caused by switching power supplies, the effect can be more
difficult to resolve, since the signals can occur at more noticeable frequencies: although the supplies
usually switch at frequencies too high to hear, the frequency is often modulated by variations in the
load current over time, resulting in a continuous modem-like chirping in which can be heard particular
events such as computer screen updates, disk activity etc.). Another problem is that even heavy
ground cabling may not reduce the effect of the interference, since high-frequency currents may not
see much less resistance in a thick conductor than a thin one.
How do the equipment manufacturers get away with this? Surely there are stringent regulations
covering conducted and radiated emissions? Well that's true, but the level of emissions which can
result in audible degradation of low-level, unbalanced audio interconnections are well below
legislation levels. Unfortunately, computer power supplies (and especially the switching wall-warts
and line-warts which power notebook computers and other small items) are amongst the worst
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offenders.
Vinyl decks
Titan is equipped with an RIAA de-emphasis filter in analogue inputs 1 and 2 to allow direct
connection of a vinyl deck, as described in the Analogue inputs section. Since vinyl decks usually
have a low-level, unbalanced output it is important to minimise interference as discussed above when
connection a vinyl deck.
Since most magnetic cartridges require a higher input impedance than that of the Titan microphone
preamplifier input, it is usually best to connect a vinyl deck to the instrument inputs using a pair of
phono-to-mono-jack cables. The instrument gain controls can then be set to an appropriate level for
the particular cartridge. The 1MR input impedance of the instrument inputs will work satisfactorily
with most magnetic phono cartridges (which are 'moving magnet' types), but with some cartridges,
improved frequency response and noise levels can be achieved by fitting the cartridge's required load
resistance (usually 22kR or 47kR) across the instrument input terminals; this is best achieved by
soldering it inside the jack. Moving coil cartridges have a lower output level and require a lower
preamplifier input impedance. These are best connected to Titan's mic inputs, or may require a
dedicated preamplifier.
Most vinyl decks have a ground wire separate from the audio connectors. Connection of this wire for
lowest hum is often a matter of trial and error. Ideally this should be connected to Titan's analogue
signal ground (the outer of the instrument input jacks, or pin 1 of the mic input XLRs). Since no
dedicated terminal exists on Titan, it is usually easiest to connect the wire to the outer of one of the
deck's unbalanced output connectors. In some situations, a direct connection to local mains ground
may work better.
In summary
· Use good-quality cables with reputable connectors;
· Use balanced connections where possible; if you must use unbalanced connections, keep them
short;
· Ensure that signals passing between equipment do so at as high a level as is practical;
· If switching interference is heard, try to identify the source equipment by unplugging things one by
one. When you find the culprit, either re-plug it a long way from the audio equipment, or use a
power filter, or both.
7.5
Digital interconnections
It is understandable that little attention is usually paid to the quality of digital audio cabling. We are
used to interconnecting our computer equipment with low-cost cables without mishap, and with digital
audio it's rather logical to assume that no sound quality issues exist since we are simply moving
digital data around.
But the choice of digital audio cabling can be important, because the problems of transmitting digital
audio data aren't really the same as for computer data at all.
Data integrity issues
In general, digital audio interfacing problems are usually (but not always) the result of inadequate
interface bandwidth, which is most often due to the choice of cabling. In extreme cases this can
result in loss of data (and resulting dropouts in the audio) because (unlike computer interconnection
protocols) simple digital audio interfaces such as AES3, S/PDIF and ADAT transmit the data only
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once, and without the possibility of error correction. Although there is a possibility that an error can be
detected, this is of little use since no correction or retransmission is possible. So, unlike a computer
interconnection, a mission-critical digital audio connection must ensure that no bit errors can EVER
occur in the data stream EVER! This can be hard to guarantee in the real world, especially when the
system sample rate is high.
This was not really much of a problem when these interfaces were first standardised, since the
bandwidth requirement was quite modest when the maximum sample rate was only 48kHz.
Unfortunately, back then, the use of analogue audio cables for digital audio transmission was actively
encouraged by the choice of XLR and RCA/phono connectors for AES3 and S/PDIF respectively,
even though they typically have poor bandwidth. But for AES3 and S/PDIF, the bandwidth
requirement is directly proportional to the sample rate, since a fixed number of audio and status bits
are transmitted per stereo sample (note that for ADAT/SMUX connections the bandwidth requirement
does NOT rise with sample rate since the number of channels carried is reduced as the sample rate
is increased instead).
Many modern digital audio devices can operate at sample rates as high as 192kHz, and (sad to say)
many digital audio cabling setups don't have the bandwidth to support this reliably. Actually, it's worse
than that - much of the 192kHz-capable equipment has digital audio ports which (either admittedly or
otherwise) don't support reliable operation at 192kHz whatever cable is used. This is particularly true
of TOSLINK ports (the optical variant of S/PDIF).
Conversion quality issues
But surely the sound quality of a digital audio setup can't depend on the choice of digital audio
cabling, so long as all the data bits get through? Sadly, and familiarly, though - it can. Because in
may cases the audio data stream is used to pass the sampling clock as well as the audio data
between equipment. If the receiving equipment gets a clock which has been degraded by a lowbandwidth interface, and if it uses this clock for A/D or D/A conversion, then the sound quality of that
box will be degraded. This effect is known as 'sampling jitter'. Unfortunately the biphase coding
scheme used in AES3 and S/PDIF is very effective at converting low cable bandwidth into clock jitter.
It should be pointed out that this is an entirely avoidable problem, since any box which relies on
deriving a jitter-free clock for A/D or D/A conversion (or for sample-rate conversion) can take steps to
eliminate incoming jitter - but many don't. The Prism Sound CleverClox technology in Titan does
exactly this, as explained in the Clocking and jitter section. This problem isn't really a cabling issue,
but an equipment design issue. However, in most cases we can't change the design of poor-quality
converters, but we can cover up their problems to some extent with good cabling!
Even though Titan is insensitive to incoming clock jitter, and even though it transmits very low jitter at
its digital audio and clock outputs, the question of cable quality may still be relevant if Titan is
transmitting to equipment which itself has poor jitter rejection capabilities. Note that audio quality
degradation by cable-induced jitter is just as much a problem at low sample rates as at high sample
rates.
Interference issues
A properly designed copper AES3 or S/PDIF interface will not cause audio-frequency ground
continuity between the connected equipments, so hum loops should not occur. However, highfrequency ground continuity is essential if EMC legislation is to be met. This means that highfrequency interference such as from poor-quality switch-mode power supplies (see the Analogue
interconnections section) can equally well be passed through copper digital audio interconnections. If
this is a problem in your system, consider using a TOSLINK connection instead.
Maximising cable performance
In general, the best copper cable for digital audio is the cable with the lowest capacitance, since that
will cause the least loss of bandwidth. For that reason, prefer cables specifically designed for digital
audio, or for analogue video; don't use analogue audio cables - they don't have the bandwidth for
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digital audio use, especially at high sample rates. Prefer also the shortest cable, since (all other
things being equal) loss of bandwidth is proportional to length.
Maximising cable bandwidth is important in optimising AES3 and S/PDIF data integrity at high sample
rates such as 192kHz, and in optimising conversion quality in systems which include poor-quality
converters. It is of little importance in protecting the data integrity of low sample rate systems, unless
cable lengths are very long.
We are taught to choose cables of the correct impedance for the job. Whilst this doesn't have a direct
impact on bandwidth, it can have a significant effect on data integrity at high sample rates and where
cabling is short (and let's face it: at 192kHz cables had better be short...) because the reflections
resulting from an impedance mismatch can affect the eye pattern at the receiver horribly. This can be
much worse where non-matched connectors (such as XLRs) are present part way along the cable,
such as in the case of 'breakout' cabled systems. For this reason, it may be better at high sample
rates to use a continuous cable suitably terminated at each end rather than a 'breakout' arrangement.
In summary
· Use good-quality high-bandwidth cables - this means cables specifically designed for digital audio,
or perhaps for analogue video - analogue audio cables are not suitable;
· Don't use cables that are longer than you need;
· At high AES3 or S/PDIF sample rates, consider eliminating 'breakout' connectors in the line by
using a single length of high-bandwidth cable suitably terminated at each end;
· Consider using TOSLINK interconnections in systems where switch-mode interference is a
problem, but remember that poor-quality TOSLINK cables can have very low bandwidth.
© 2013 Prism Media Products Ltd
1.52
Part
8
Specifications
Prism Sound Titan
8
Operation Manual
Revision 1.00
Specifications
Front Panel
Instrument inputs 1&2: Two 6.3mm mono jack sockets
Headphone outputs 1&2: Two 6.3mm stereo jack sockets, with illuminated volume controls
Master volume control: Assignable to any selection of outputs, with LED halo indication
Multi-segment, multi-color bargraphs with overload indication; eight for
Level meters:
analog, two for digital, assignable to inputs or outputs
Input selector indicators: Indicate modes of analog inputs as mic/line/instrument; plus phantom
power indicator for mic mode
For each analog input, lit when Overkiller limiters are acting
Overkiller-active
indicators:
Digital input indicators: Input unlocked, and SRC (sample-rate converter) selected
Digital output indicator: SRC (sample-rate converter) selected
Master, lit when interface is in local sync
Sync indicator:
Indicates whether the host connection is via USB, Ethernet or MDIO
Host indicator:
module
With standby indicator (also flashes when unit is in 'identify' mode)
Standby button:
Rear Panel
Mic/Line inputs 1-4:
Line inputs 5-8:
Line outputs 1-8:
Digital inputs:
Digital outputs:
Wordclock I/O:
USB port:
Ethernet port:
MDIO expansion slot:
Mains power:
Software Support
Mac OS support:
Windows OS support:
Mac audio driver:
Windows audio driver:
Control Panel app:
Four Combo sockets; XLR for mic input, TRS jack (balanced or
unbalanced) for line input
Four 6.3mm TRS jack sockets (balanced or unbalanced)
Eight 6.3mm TRS jack sockets (balanced or unbalanced)
RCA socket for S/PDIF in, TOSLINK for S/PDIF or ADAT/SMUX in; (RCA
can operate as AES3 input using XLR-RCA adapter supplied)
RCA socket for S/PDIF out, TOSLINK for S/PDIF or ADAT/SMUX out;
(RCA can operate as AES3 output using RCA-XLR adapter supplied)
Two BNC sockets, output and input (75R)
USB 2.0 B type device socket
RJ45 100BaseT socket, for factory and future use
Accommodates optional MDIO (multi-channel digital IO) module for
alternative host connection
3-pin 6A IEC inlet
OS X 10.5 or later, Intel platform
Windows Vista, 7, 8 or later (32 or 64 bit)
Core Audio device
ASIO or WDM device
Graphical user interface for control of Titan unit under Mac OS X or
Windows
© 2013 Prism Media Products Ltd
1.54
Prism Sound Titan
Analog Line Inputs
Configuration:
Input sensitivity:
Input impedance:
Unbalanced mode:
Total harmonic
distortion:
THD+n:
Dynamic range:
Gain accuracy:
LF roll-off:
HF roll-off:
Operation Manual
Revision 1.00
Electronically balanced, with fully-balanced analog signal path
Switchable ‘+4dBu’ (0dBFS=+18dBu) or ‘-10dBV’ (0dBFS=+6dBu)
14.5kR
Automatic
-117dB (0.00014%, -0.1dBFS)
-111dB (0.00028%, -0.1dBFS)
116dB (-60dBFS)
±0.05dB
-0.05dB at 8Hz; -3dB at <1Hz
fs=44.1kHz: -0.05dB at 21.1kHz; -3dB at 22.0kHz
fs=48kHz: -0.05dB at 23.0kHz; -3dB at 23.9kHz
fs=96kHz: -0.05dB at 32.0kHz, -3dB at 47.9kHz
fs=192kHz: -0.05dB at 32.0kHz, -3dB at 78.0kHz
20Hz..20kHz: >70dB
CMRR:
Inter-channel cross-talk: 1kHz: <-140dB; 20Hz..20kHz: <-120dB
10Hz..5kHz: ±0.25º, 5kHz..20kHz: ±1.0º, 20kHz..50kHz: ±2.0º
Inter-channel phase:
Progressive limiter, auto-aligning, selectable per channel
Overkiller:
High-pass filter, -3dB at 80Hz, 40dB/decade (selectable for channels 1-2;
Impact filter:
whether in line, mic or instrument mode)
RIAA de-emphasis filter: Response accuracy: ±0.22dB at fs=44.1kHz; ±0.14dB at fs=48kHz;±
0.015dB at all other sample rates
Allows direct connection of mid-side mics, or non-matrix mic-preamps
MS matrix:
(selectable for all analog input channels, whether in line or mic mode)
Microphone Preamplifiers
Electronically balanced, with fully-balanced analog signal path
Configuration:
10dB to 65dB in 1dB steps (0dBFS = -56dBu to -1dBu)
Gain:
±0.05dB
Gain accuracy:
5.5kR
Input impedance:
+10dB gain: -116dB at -0.1dBFS (0.00016%)
THD
+40dB gain: -110dB at -0.1dBFS (0.00032%)
+10dB gain: -108dB at -0.1dBFS (0.00040%)
THD+n:
+30dB gain: -128.5dBu (0R source); -126.3dBu (150R source)
Equivalent input noise
+40dB gain: -130.9dBu (0R source); -127.6dBu (150R source)
(EIN):
+50dB gain: -131.2dBu (0R source); -127.7dBu (150R source)
+60dB gain: -131.4dBu (0R source); -127.8dBu (150R source)
-0.05dB at 20Hz; -3dB at 5Hz
LF roll-off:
As per Analog Line Input data (dependent on fs)
HF roll-off:
50Hz/60Hz: >110dB at all gains
CMRR:
1kHz: >100dB at all gains
20kHz: >90dB at all gains
+48V, switchable per channel
Phantom power:
-20dB, switchable per channel
Pad:
Instrument Preamplifiers
Configuration:
Gain:
Gain accuracy:
Input impedance:
Unbalanced, high impedance buffer
10dB to 65dB in 1dB steps, 18dB pad (0dBFS = -38dBu to 17dBu)
±0.05dB
1MR
© 2013 Prism Media Products Ltd
1.55
Prism Sound Titan
Analog Line Outputs
Configuration:
Output amplitude:
Output impedance:
Unbalanced mode:
Total harmonic
distortion:
THD+n:
Dynamic range:
Gain accuracy:
LF roll-off:
HF roll-off:
Operation Manual
Revision 1.00
Electronically balanced, with fully-balanced analog signal path
Switchable ‘+4dBu’ (0dBFS=+18dBu) or ‘-10dBV’ (0dBFS=+6dBu)
100R balanced, 50R unbalanced
Automatic, with bootstrapping level compensation
-107dB (0.00045%, -0.1dBFS)
-106dB (0.00050%, -0.1dBFS)
115dB (-60dBFS)
±0.05dB
-0.05dB at 8Hz; -3dB at <1Hz
fs=44.1kHz: -0.05dB at 21.4kHz; -3dB at 22.0kHz
fs=48kHz: -0.05dB at 23.2kHz; -3dB at 23.9kHz
fs=96kHz: -0.05dB at 32.0kHz, -3dB at 47.8kHz
fs=192kHz: -0.05dB at 32.0kHz, -3dB at 76.0kHz
>50dB
Output balance:
Inter-channel cross-talk: 1kHz: <-135dB; 20Hz..20kHz: <-120dB.
10Hz..5kHz: ±0.4º, 5kHz..20kHz: ±0.25º, 20kHz..50kHz: ±0.5º.
Inter-channel phase:
Digital Input
S/PDIF (RCA or TOSLINK), ADAT, ADAT SMUX (TOSLINK)
Formats supported:
Sample rates supported: S/PDIF (2 channel): 44k1, 48k, 88k2, 96k, 176k4, 192k
ADAT (8 channel): 44k1, 48k; ADAT SMUX (4 channel): 88k2, 96k
Ignored
Channel Status:
24 bits
Word-length:
Via S/PDIF RCA, using XLR-RCA adapter (supplied)
AES3 operation:
Selectable at S/PDIF input, allowing input at any sample rate
Sample-rate converter
(SRC):
Maintained (allows recording of Dolby or DTS streams)
Bit-transparency:
Digital Output
S/PDIF (RCA or TOSLINK), ADAT, ADAT S/MUX (TOSLINK)
Formats supported:
Sample rates supported: S/PDIF (2 channel): 44k1, 48k, 88k2, 96k, 176k4, 192k
ADAT (8 channel): 44k1, 48k; ADAT S/MUX (4 channel): 88k2, 96k
Full implementation, Consumer (S/PDIF) or Professional (AES3)
Channel Status:
24 bits, or reduction to 16 bits using flat TPDF dither or Prism Sound
Word-length:
SNS (Super Noise-Shaping - four alternative shapes available)
Via S/PDIF RCA, using RCA-XLR adapter (supplied)
AES3 operation:
Selectable at S/PDIF output; output rate can be referenced to
Sample-rate converter
Wordclock, DI or local clock at 44k1, 48k, 88k2, 96k, 176k4 or 192k
(SRC):
Maintained in 24 bit mode (allows playback of Dolby or DTS streams to
Bit-transparency:
external decoder)
Sample-rate converter
(SRC)
THD+n:
Dynamic range:
<-137dB (0.000014%, -0.1dBFS)
>138dB (0.000013%, -60dBFS)
© 2013 Prism Media Products Ltd
1.56
Prism Sound Titan
Operation Manual
Revision 1.00
Synchronization
44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz
System sample rates:
Synchronization sources: Master: Local
Slave: Wordclock, DI (S/PDIF input) or ADAT
+/-50ppm
Local clock accuracy:
60dB/decade above 100Hz
Jitter rejection:
44.1k: 0.57ms; 48k: 0.52ms; 88k2: 0.20ms; 96k: 0.18ms; 176.4k:
Internal mixer delay:
0.09ms; 192k: 0.08ms
(total analog in to out)
Physical
Dimensions:
Weight:
Mains voltage:
Power consumption:
Fuse rating:
Operating ambient:
Table-top (including feet): 446x290x50mm
1U rack-mount (including optional ears): 483x290x44mm
3.8kg.
90VAC-250VAC, 50-60Hz
15W
0.5A(T), 20mm, glass
0 to 35ºC, 85% maximum relative humidity
Performance Plots
© 2013 Prism Media Products Ltd
1.57
Prism Sound Titan
© 2013 Prism Media Products Ltd
Operation Manual
Revision 1.00
1.58
Prism Sound Titan
Operation Manual
Revision 1.00
Except where otherwise stated, audio performance data are typical, RMS, unweighted, 20Hz..20kHz
figures, measured at 997Hz, using fs=96kHz and '+4dBu' sensitivity settings.
In keeping with our policy of continual development, specifications are subject to amendment without
notice.
E&OE. All Trade Marks acknowledged.
© 2013 Prism Media Products Ltd
1.59
Core Audio
Index
-DDelay 26
Device Manager 34
DI inputs 22
DI synchronization 24
Digital inputs 23, 37
Digital interconnections 50
Digital outputs 25, 38
Dither 26, 45
DO synchronization 26
Driver updates 19
Drivers 39
---20dB mic pads
37
-2256x clock
29
-AADAT inputs 23
ADAT mode 35, 37, 38, 39
ADAT mode control 35
ADAT outputs 25
AES11 24, 26, 29
AES3 outputs 25
Analogue inputs 22, 37
Analogue interconnections 48
Analogue outputs 24, 38
Architecture 22
ASIO 14, 39
Assignable level control 27, 38
Async (ASNC) indicator 23, 37
-BBalanced connections
Baseclock 29
Block diagram 22
Breakout cables 50
Brightness, front panel
Buffer control 35
Buffer size 35, 42
12, 39
-EEarthing 48, 50
Ethernet interface
29
-FFaders 26
Features 6
Firmware updates 19
Firmware version 35
Foldback mixers 39
FP Meters control 35
Front panel 29
Fuse locations and ratings
32
22, 24
-G35
-CCable impedance 50
Cabling 50
CleverClox 43
Clock Out control 35
Clocking 43
Connectors 29, 31, 50
Control Panel app 34, 39
Cooling 32
Getting started, Mac 10
Getting started, Windows
Glitches 42
Grounding 48, 50
10
-HHeadphone outputs 27, 38
Help button 35
High-pass filter 23, 37
Host indicator 28, 29
Host interface 29
HPF 23, 37
Hum loops 48, 50
-IIdentify button 35
Impact filter 23
Input controls 37
Input mode 22
Input selection indicators 29
Inputs tab 37
Inputs, ADAT 23
Inputs, analogue 22, 27
Inputs, digital 23, 27
Inputs, S/PDIF 23, 24
Installation, Mac 12
Installation, Windows 14
Instrument inputs 22, 37
Interconnections 48, 50
Interference 48, 50
-JJitter 43, 50
JTEST 43
-LLatency 26, 42
LED brightness 35
LED indicators 29
Level control 27
Level meters 27
Line inputs 22, 37
Line outputs 38
Load button 35
Local sync 32
Lock button 38
Low-latency mixers 39
-MMac 10, 12, 34
Manual 7
Master indicator 29
MDIO expansion slot
Meter panel 29
Meters 27
Mic input pads 22
Mic inputs 22, 37
Mic pads 22, 37
28, 29, 31
Microphone preamplifiers
Mixer controls 39
Mixers 26, 38, 39
Monitor control 27
MS matrix 23, 37
Multiple units 19
Mute button 26, 27, 38
22
-NNoise-shaping
26, 45
-OOperation Manual 7
Operation of multiple units 19
Operation without a computer 32
OS X 10, 12, 39
OS X versions 7, 10, 12
Output controls 38
Output ganging 24, 26, 27
Output mixers 26
Output mute 27
Outputs tab 38
Outputs, ADAT 25
Outputs, AES3 25
Outputs, analogue 24, 27
Outputs, digital 25, 27
Outputs, headphone 27
Outputs, S/PDIF 25
Over-dubbing 42
Overkiller 23, 27, 37
Overload indicators 27
Overview 6
-PPan pots 26
PC 10, 14
Phantom power 22, 37
Phase-reverse 37
Phono cartridges 23, 48
Prism Sound, CleverClox 43
Prism Sound, SNS (Super Noise-Shaping)
45
-QQuick start guide, Mac
10
26,
Quick start guide, Windows
10
-U-
-RRack mounting kit 32
Rear panel 31
Re-dithering 26, 45
Ref Sync 24, 26, 29, 43
Reference sync 24, 26, 29, 43
RIAA de-emphasis filter 23, 37, 48
Routing matrix 26, 27
Rubber feet 32
-SS/PDIF input 23, 24
S/PDIF output 25
Sample rate 50
Sample Rate control 35
Sample-rate converter 24, 25
Sampling jitter 43
Save button 35
Serial number 35
SNS (Super Noise-Shaping) 26, 45
SNS Logo, use of 45
Software 34
Software updates 19
Software version 19
Solo 26
Specifications 54
SRC 24, 25, 29
SRC control 35
Stability 42
Stand-alone operation 26, 32
Switched-mode power supplies 48, 50
Sync Source control 35
Synchronization 24, 26, 29
Synchronization source 32
System requirements 7
-TTechnical topics 42
Titan Control Panel app
TOSLINK 50
TPDF 26, 45
34
Unbalanced connections 22, 24
Unit settings 35
Unlocked (ULOK) indicator 23
Unlocked (UNL) indicator 37
Updating software 19
-VVinyl decks 23, 48
Volume control 27
-WWDM audio 14, 39
Windows 10, 14, 34, 39
Windows versions 7, 10, 14
Wordclock 24, 26, 29, 43
Word-length 26, 45